Overweight and Obesity Epidemic in America – Part II: Obesity Prevalence and Trends Among Children and Adolescents

Michael G. Garko, Ph.D.Host – Let’s Talk Nutrition

Introduction

The health of America’s youth is dangerously close to being in jeopardy. Many health practitioners, experts and researchers would contend that it is already in peril and representing a serious threat to the health of the nation.

This pediatric concern for the nation’s youth is supported and evidenced by the increased prevalence of obesity and other chronic health conditions among children over recent decades. Specifically, the rate of increase of childhood chronic conditions (e.g., obesity, asthma, other physical conditions and behavior/learning problems) rose from 12.8% in 1994 to 26.6% in 2006 (see Van Cleave et al., 2010).

While an increase in the prevalence of any chronic health condition among America’s youth merits attention, obesity among children and adolescents is of special importance because it is linked to other serious health conditions (e.g., insulin resistance/metabolic syndrome, high cholesterol, high blood pressure, type 2 diabetes and early signs of heart disease), which are being diagnosed in children and adolescents. For example, in a recent study, obese children as young as three years of age were found to have elevated levels of C-reactive protein (CRP). CRP is an inflammation marker and early warning sign of vascular damage leading to coronary heart disease, a condition from which adults typically suffer (Skinner et al., 2010).

As the second installment in the series on the Overweight and Obesity Epidemic in America, the November, 2010, issue of Health and Wellbeing Monthly sketches the prevalence and trends of overweight and obesity among children and adolescents.

Overweight and Obesity Defined

The term “overweight” refers to an excessive amount of body weight, which can be constituted of muscle tissue, bone, adipose or fat tissue and water, while the term “obesity” refers to an excessive amount of adipose or fat tissue (see National Institute of Diabetes and Digestive and Kidney Diseases, 2010).

Body Mass Index

The statistics and trends reported below are from the 2007–2008 National Health and Nutrition Examination Survey (NHANES) and from NHANES III (1988-1994). Body mass index (BMI) was used in the NHANES to determine who in the survey was overweight, obese or extremely obese. As a formula, BMI is expressed as weight in kilograms divided by height in meters squared (kg/m2). Children with BMI values at or above the 95th percentile of the gender-specific BMI growth charts are categorized and defined as obese (Ogden & Carroll, 2010).

Obesity Prevalence and Trends Among Children and Adolescents

Findings from the 2007-2008 NHANES show that an estimated 16.9% of children and adolescents aged 2-19 years are obese. While there was an increase in the prevalence of obesity between the selected years of 1976-1980 and 1999-2000, there was no significant increase in the prevalence of obesity between the selected years of 1999-2000 and 2007-2008.

Specifically, Table 1 shows that from 1976-1980 to 2007-2008 obesity among preschool children aged 2-5 increased from 5.0% to 10.4% and among children aged 6-11 from 6.5% to 19.6%. From 1976-1980 to 2007-2008, obesity among adolescents aged 12-19 increased from 5.0% to 18.1% (Ogden & Carroll, 2010). Figure 1 provides a clear picture of the trends in obesity among children and adolescents in the United States from 1963 to 2008.

Racial/Ethnic Differences

Race and ethnicity make a difference when it comes to the prevalence of obesity among American children and adolescents.

Boys and girls. Table 2 shows the estimated prevalence of obesity by race/ethnicity for boys and girls from 1988-1994 to 2007-2008. An analysis of NHANES data for the selected years from 1988-1994 to 2007-2008 reveal that for boys and girls aged 12-19 obesity prevalence increased and that the increase in the prevalence of obesity for boys and girls aged 12-19 cut across racial/ethnic boundaries (i.e., non-Hispanic white, non-Hispanic black & Mexican American) (Ogden & Carroll, 2010).

Boys. While from 2007-2008 it was higher among Mexican-American adolescent boys (26.8%) compared to non-Hispanic white adolescent boys (16.7%), there was no significant difference in obesity prevalence from 1988 to 1994 between Mexican-American and non-Hispanic white adolescent boys.

Specifically, for the selected years from 1988-1994 to 2007-2008 obesity prevalence among boys increased in the following way:

Figure 2 shows the increase in obesity prevalence for boys aged 12-19 by race/ethnicity from 1988-1994 to 2007-2008.

Girls. From 2007 to 2008, there were significantly more non-Hispanic black adolescent girls (29.2%) than there were non-Hispanic white adolescent girls (14.5%). In a similar fashion, from 1988 to 1994 there were significantly more non-Hispanic black adolescent girls (16.3%) than there were non-Hispanic white adolescent girls (8.9%).

Specifically, for the selected years from 1988-1994 to 2007-2008 obesity prevalence among girls across racial/ethnic groups increased in the following way:

Figure 3 shows the increase in obesity prevalence for girls aged 12-19 by race/ethnicity from 1988-1994 to 2007-2008.

Conclusion

Obesity is among the most serious, if not most serious health threat to American children and adolescents in the 21st century. Seventeen percent of U.S. children and adolescents aged 2-19 years are obese. Nearly one third of children in the United States are currently either overweight or obese with BMI levels ≥ 85th percentile (Ogden et al., 2010). This represents a tripling of overweight and obesity prevalence among children since 1980, with racial/ethnic disparities existing among adolescents. Compared to non-Hispanic white boys and girls, non-Hispanic black boys and girls and Mexican-American boys and girls are significantly more likely to be obese.

Rather than living healthy and vital lives during their formative and childhood years, children find themselves suffering from adult diseases such as insulin resistance/metabolic syndrome, high cholesterol, high blood pressure, type 2 diabetes and early signs of heart disease, all of which carry over into adulthood. More and more children under the age of 10 are being diagnosed with what used to be called “adult onset” type-2 diabetes, which occurred nearly exclusively in adults who were middle-aged and overweight. According to Dr. David L. Katz, it is not so surprising to find 16-, 17- and 18-year-olds suffering from adult onset diabetes for a decade or more. He reported knowing of a case of a 25-year old who underwent coronary angioplasty and a 17-year old obese boy who received a triple coronary bypass (see Katz, 2010).

All of the grim statistics surrounding the overweight and obesity epidemic among adults, children and adolescents beg at least two questions: 1. “What caused this unprecedented increase in the prevalence of overweight and obesity among America’s Youth?” and 2. “How can and should the epidemic of overweight and obesity in America be addressed and corrected?” Much has been written by many to answer both of these questions. On the on hand, identifying the cause(s) of the overweight and obesity epidemic is, while challenging and complicated, achievable. On the other hand, the solutions to resolving the crisis are far complicated on a number of levels, including exactly what the most effective solutions would be and how to get them implemented on an individual, group, organizational and societal level.

In upcoming issues of Health and Wellbeing Monthly, attention will be devoted to what experts have identified as the causes of and solutions to the overweight and obesity epidemic in America among its adults and youth, along with critical commentary.